Are screens at night hurting your future kids?

Maybe think twice about checking your phone at 2 a.m.

Two too many screens in a dark room, young man.
(Photo: Dean Drobot/Shutterstock)

There's a force out there that's been slowly and subtly affecting our lives, and at this point it doesn't seem as if there's any place to hide from it. What exactly is this force? Excessive exposure to dim light during naturally dark hours.

I'm going to go ahead and take a shot in the dark and guess that there are few people who step away from their smartphones, tablets or laptops once the sun goes down. And there are probably a lot of us who doze off in front of the television. While exposure to the dim light of screens at night may seem trivial and harmless, various studies have suggested that this exposure disturbs our circadian rhythm, and that it may have effects on our health — including increasing the risks for diabetes and some cancers.

The researchers built off previous findings that showed the immune systems of Siberian hamsters — which are naturally nocturnal animals — were weakened when they were exposed to dim light during nighttime hours. This time, the researchers set out to see if the effects could potentially be multi-generational due to epigenetic changes, changes that occur due to outside stimulus without alteration of the DNA sequence itself. As it turns out, baby hamsters whose parents were exposed to altered light cycles were born with weakened immune and endocrine systems.

"This suggests that circadian disruptions can have long-ranging effects in offspring and that's concerning," said lead author Yasmine Cisse, a graduate student of neuroscience at Ohio State University.

No screens for hamsters

For nine weeks, the researchers exposed adult female and male hamsters to two different light cycles. The hamsters were either exposed to the standard light day and dark night cycle, or a cycle in which the nights were accompanied by artificial dim lights.

At the end of the nine-week period, the hamsters were able to mate, and they did so in four different groups. The groups consisted of exposed males with unexposed females, exposed females and unexposed males, females and males that were both exposed and females and males that lived in standard light conditions. After the hamsters finished mating, they and their offspring all lived under standard light conditions. Despite being raised under standard light cycles, the offspring of parents that were exposed to dim light at night had impaired immune and endocrine systems, specifically in a way that made it difficult for the hamsters to fight off foreign stimulus.

What the researchers found particularly interesting was that the epigenetic changes were passed on from both females and males. "These weren't problems that developed in utero. They came from the sperm and the egg," said senior study author Randy Nelson, professor and chair of neuroscience at Ohio State's University Wexner Medical Center. "It's much more common to see epigenetic effects from the mothers, but we saw changes passed on from the fathers as well."

The negative impacts of circadian rhythm disruption may reach far beyond what we previously thought. No studies of this kind have yet to involve humans, but the studies themselves show that the effects of dim light at night could be more of a serious threat to health in ways we haven't yet considered. We probably won't be tossing out all of our devices to keep completely stable immune systems for the sake of ourselves and our children, but the research suggests that we might want to be mindful of how often and when we use our devices.

So if you're reading this and it's past your bedtime, you might want to just give it a rest and get a healthy night's sleep.